Pure White Light Emitting Tetrakis β-diketonate Dysprosium Complexes for OLED Applications

In this work, highly photoluminescent tetrakis β-diketonate of rare earth complexes M[Dy(acac)4] (M = Li+, Na+, K+) were synthesized to study the sensitization effect on Dy3+ ion by β-diketonate ligand. Emission spectra show intense peaks at 485 nm and 577 nm in blue and yellow region for the transition 4F9/2→6H15/2 and 4F9/2→6H13/2 of Dy3+ ion respectively. Blue to yellow intensity ratio was modified by introducing counter cation. The excitation spectra show an intense peak at 330 nm due to the absorption of π – π* band in ligand. Diffused reflectance (DR) spectra and excitation spectra show the similar peaks for the f-f transitions of Dy3+ which confirms that ligand to Dy3+ ion energy transfer occurred efficiently. The CIE chromaticity diagram shows that pure white light was achieved for sodium complex. It was found that excited state lifetime of sodium complex is very short (0.1378 ms and 0.042 ms) for the 4F9/2→6H15/2 and 4F9/2→6H13/2 transition of Dy3+ ion. It can be used for white organic light emitting diode (OLED) applications due to it's short life time and CCT value compatible with day light.